Telescoping ladder



Patented Oct. 15, 1929 UNITED STATES RALPH OTTO CLARK, F ESTHERVILLE, IOWA TELESCOPING LADDER Application flied september 2s, 1927. serial No. 222,490.

This invention relatesvto telescoping ladders, and one object is to provide a ladder the parts of which are formed of pressed sheet metal and having two sections adapted to,

telescope one within the other.

Another object is to provide such ladder with the Jtelescoping sections thereof so connected by Vpulleys and cables' operated by a crank, that the said sections may be readily and handily expanded for use or telescoped together', as desired.

In the drawing Figure 1 is a side elevation of the ladder,

shown as leaning against a supporting structure;

Figure 2 is a relatively enlarged front elevation of portions of the telescopingladder sections, taken at their point of connection; Figure 3 is a transverse section on the line 3 3 of Figure 2;

Figure 4 is a vertical, longitudinal section taken through portions of the two telescoping side rails ofthe ladder sections at their juncture;

Figure 5 is a detail of one of the ladder steps showing the formation of same from sheet metal, the right hand end fold being omitted so as to reveal clearly the method of folding the sheet metal. u

In carrying out this invention, I provide a lower ladder section A and an upper section B. These sections are both formed of lengths of sheet metal bent and formed and folded upon longitudinal lines of fleXure into the shapes shown, and with the upper section B adapted to telescope within the lower section A. For this purpose the sheet metal strip of each lower side rail C is flexed into a hollow and open tubular structure, rectangular in cross section, having the outer side wall 1, the inner' side wall 2, the front and rear walls 3 and 4, the spaced transverse inner front wall 5 and partition 6 adjacent the front wall 3, the inner longitudinal side opening or parting 7 adjacent the rear wall 4, and the marginal flanges 8 at the opening 7. The sheet metal strip of the upper side rail D is flexed into a Y hollow structure, rectangular in cross section, having the side wall 9, the front and rear walls 10 and 11, the inner side walls 12 meeting centrally at 13 and the spaced transverse webs 14. vThis rectangular structure represented as a whole at D is adapted to telescope within the structure of the lower rail C formed by the side wall 1, the front and rear walls 4 and 5 and the flanges 8. The side rails C and D of the sections A and B are connected by steps E. These steps are likewise formed of strips of sheet metal each cut and iiexed to form the tread face 15, the inset perl 'pendicular webs 16, the end folds 17 with the projecting flanges 18 pierced with rivet holes 19 for attachment tothe side rails as shown at V20, and the lower fianges 21 extending pen pendi'cular to the webs 16. 65 As stated, the upper section B is telescopi-` cally mounted within the `lower section A, and the upper end of the lower section A is reinforced with a number of cross braces 22 which are likewise riveted to the side rails C, as shown at 23. Pulleyshafts 24,` 25 are journaledl transversely near the lower and upper ends of the lower section A, between the webs 5 and 6, the said shafts havingbearings through the walls 1 and 2. Pulleys 26, 75 27 are rigidly mlounted upon the ends of the shafts A24, 25, within the side rails C, long slots 28 being cut through the webs 5 and 6 to accommodateV said pulleys and cables 29.

The cables 29` areattached at one end to the 8o j lower pulleys 26, and after being wound aroundsaid pulleys the requisite number of times, are passed up over the upper pulleys 27 and through the slots 28 and have their ends secured at 30 to the lower ends ofthe upper rails D. A ratchet wheel 31 is rigidly mounted on an end of the llower shaft 24 eX- tended through one of the rails C, and a pawl 32 piVoted on thev said rail C, as at 33, controls the ratchets 31 on rotation of the shaft 24 to wind the cables 29 upon the pulleys 26 but of course by releasing the said pawl the said cables may be allowed to unwind from the said pulleys. A hand crank 34 at the eXtended end of the lower shaft 24, affords means for turning the lower shaft 24 and so operating the mechanism of the ladder.

In use the upper section B may be readily extended by rotating the crank 34, or may be telescoped back into the lower section A by EID releasing the pawl 32. This structure therefore affords a very light and strong as well as convenient telescoping ladder.

It will be noted that in the process of telescoping the upper section into the lower section, the ends of the steps E of the upper section traverse the inner side openings 7 of the rails C of the lower section.

lllhile I have here described a preferred form of construction, it is understood that the structural details may be varied, within the scope of the appended claims. Y

I claim:

l. An extensible ladder as described, comprising a lower section and an upper section adapted to be vslidably telescoped in and extended from the lower' section, means slidably engaging said upper section in telescoped relation with said lower' section, said lower section having side rails each including a longitudinally extending box-like housing, and operative means for extending said upper section from said lower section, said operative means being positioned interiorly said housing.

2., An extensible ladder as described, comprising a lower section and an upper section adapted to slidably engage the lower section, said upper section comprising a single sheet of metal formed and folded upon longitudinal lines of flexure to form a channel shaped member, the terminal portions of the flanges thereof being returned upon themselves to form opposed box-like members, the lower section comprising a single sheet of metal formed and folded upon longitudinal lines of fiexureto form a channel shaped member slidably embracing the upper section, one of the flanges being flexed upon itselfyto form a box-like housing and further returned upon itself to form a partition interiorly said boxilxe housing, and operative means for extending said upper section fromsaid lower section, said operative means being mounted f on said partition interiorly said housing.v

3. In a device of the kind described, a side rail of a ladder formed of a single sheet of metal formed and folded upon longitudinal lines of flexure to form a partition, a box girder formed around said partition and interiorl y partitioned thereby, the terminal portion of the sheet` being extended from the box-girder and bent right angularly to form a wall parallel with and spaced from said girder.

4. In a device of the kind described, a side rail of a ladder formed of a single sheet of metal formed and folded upon longitudinal lines of flexure to form a partition, inner and outer front walls spaced from opposite sides of the partition and Connected together therearound to form a box-like housing, the sheet of metal being extended laterally from the outer front wall and formed with a right angularly extending rear wall parallel with and spaced from the inner front wall and having a flange extending towards said inner front wall, said inner front wall being also flexed upon itself to form a flange aligned with and extending towards said first mentioned flange.

5. In a ladder-of the kind described, a side rail formed of a single piece of metal having one of its longitudinal side portions longitudinally flexed upon itself to form a box-like structure, the side terminal portion being further longitudinally flexed upon itself to form a longitudinally extending web disposed transversely interiorly said box-like structure, and the other side portion of the piece of metal being longitudinally flexed to form a longitudinally extending wall oppositely said box-like structure, the side terminal portion of said second mentioned side portion being further turned right angularly towards said box-like structure, the edge of said second mentioned terminal portion being spaced from said box-like structure.

6. In a ladder of the kind described, a side rail formed of a single sheet of metal formed and folded upon longitudinal lines of flexure so as to form an outer side wall, and front and rear walls flexed right-angularly to the side wall, the front wall being further flexed right-angularly in parallelism'A with the side wall to form an inner side wall, said inner side wall being further flexed upon itself to form a flange parallel to the inner side wall, the terminal portion of said flange being further flexed to form an inner front wall parallel with the rst mentioned front wall, said innerfront wall being flexed parallel with and engaging said first mentioned side wall and further flexed right-angularly thereto to engage said inner side wall.

In testimony whereof I affix my signature.

RALPI-I OTTO CLARK. 

